Re: Centrino CpuFreq
Jochen Schulz schrieb:
> * =?gb18030?Q?=C0=EE=D1=E5_Li_Yan?=:
>> My T42's CPU can run @221Mhz under windowsXP,
> How do you tell? Do you use something like SpeedswitchXP?
>> but with powersave governer provided by Linux 2.6.9, it's
>> cpuinfo_min_freq is 600Mhz. Any ideas?
I found a similar issue when I accidently loaded the "wrong" cpufreq
driver for P4 with powernowd. Suddenly /proc/cpuinfo showed frequencies
down to 200 MHz (the Bogomips also went down).
So I searched a little bit. People seem to think that those 600Mhz is
kind of hardcoded to the Centrino chipset. Taking a closer look to the
Intel Docu I found that the Intel specifications seem to be merely
recommendations. Other combinations of Frequency and Voltage are
possible. The docu regarding voltages clearly shows that there are
voltages possible other than those in the Freq/Voltage table.
I got curious and played around a little bit: On my centrino I could
lower the frequency down to 100 Mhz. Lower frequencies caused the
cpuinfo display to be messed, but frequency down to 100Mhz seem to be
stable. To be clear: Those tricks are not official language! But my accu
now works conspiciously longer :-)
I do not know wether this can cause some damage so I cannot recommend
doing such things.
> I think Windows may lie to you. As far as I know Centrinos cannot run on
> lower clockspeeds than 600MHz.